Carton with multiple locking tabs



F. A. CHIDSEY, JR, ETAL 3,182,888

CARTON WITH MULTIPLE LOCKING TABS May 11, 1965 2 Sheets-sheet 1 v Filed Feb. 5,-1964 2 Sheets-Sheet 2 IF. A. CHIDSEY, JR, ETAL' cAn'rou WITH MULTIPLE LOCKING was 5 9% 5 y W5 w? Md r M: .I Q g m 8 .4 i M "Hm y w. fl J w j T w), irlTLw v m. N M: L l l May-11, 1965 Filed e t t n The present invention relates to folding cartons and more particularly to a-form of folding carton having closure flaps which are held together by multiple locking tabs.

An important object of the invention is to provide 3,182,888 Patented May 11, 1965 Along the opposite edge of the blank from closure flaps 10, 11, 13 and 14 are closure flaps 16 and 17, hinged'to side walls 1 and 2 respectively along score line 18, and closure flaps 19 and 19a, hinged to the respective edge walls 3 and 4 along such score line 18.

cooperating carton closure flaps of simple, eflicient construction having locking elements on their meeting edge portions which may be easily interlocked to provide a composite closure panel providing for maximum resist- 1 anee to unlocking forces.

An'additional object of the invention is to provide a carton construction providing cooperating end closure flaps with locking elements on their free edges having contours that provide for complete nesting of the edges of adjacent blanks cut from sheets or webs, and which thus do not require any stripping of waste parts, such locking elements further providing mutually engaging, locking edges that, once engaged, are difiicult to disengage without damage to thestructure of the locking elements.

Additional and more specific objects and advantages of the carton of the present invention will become apparent as the description proceeds.

In the drawings-- FIGURE 1 is a fragmentary perspective view, showing an end portion of a tubular carton having closure flaps in interlocked positions;

FIGURE 2 is an end view of the carton shown in FIG- URE 1, having a portion of one flap broken away to show one of the locking elements and showing the ends of the other locking elements in broken lines;

FIGURE 3 is a fragmentary cross-sectional view taken along line 3-3 of FIGURE 2',

FIGURE 4 is a fragmentary perspective view similar to FIGURE 1, but showing the closure flaps in open position;

FIGURE 5 isa plan view of the carton blank;

FIGURE 6 is a fragmentary plan view of one end portion of the carton blank which is similar to FIGURE 5, but showing a modified form of locking element} FIGURE 7 is a fragmentary perspective view of one end portion of a carton having elements constructed as shown in FIGURE 6; and

FIGURE 8 is a fragmentary end view showing the interlocked elements in broken lines.

Referring to FIGURE 5, there is illustrateda blank for a tubular carton. This blank is formed of resilient folding paperboard and comprises side walls 1 and 2, edge walls 3 and 4, and an attaching flap 5. The edge walls are defined from the side walls by respective score lines 6, 7 and 8 and the attaching fiap is defined from side wall 1 by score line 9. Along one edge of the blank are end closure flaps 10 and 11 hinged to respective side walls 1 and 2 along a score line 12 extending the length of the blank. Additional closure flaps l3 and 14 are hinged along the score line 12 to the ends of the respective edge walls 3 and 4.

The carton is prepared in tubular form, as shown in FIGURE 4, by glueing atttaching flap 5 to the inside surface of edge wall 4.

Referring to FIGURE 4-, closure flap 11 fiap'lti is formed with a single male locking element 21, identical with elements 19 and 20, and located so as to fit symmetrically between them.

First, referring in detail to element 21 on flap 10, this element has a narrow, forwardly projecting portion 22 withsquare cut ends 22a, 22a which are joined by e diagonal edges 23, 23 extending laterally and rearwardly from the portion 22. Extending rearwardly from the diagonal edges 23 are edges 24, 24a disposed at right angles to the free edge of projecting portion 22 and in parallel relation with the edges 22a. The element 21, is formed with additional edges 25, 25a meeting the inner ends of respective edges 24, 24a. These edges 25, 25a are formed by slits extending inwardly of the element 21, at right angles to edges 24, and parallel with the outer free edge of projecting portion 22.

The remainder of the edge of closure flap 10 comprises two edge portions 26 and 27, and two outwardly extending portions, indicated at 28 and 29, which, in the present instance, are substantially identical with one-half of the locking element 21. w

The portion 28 comprises a narrow edge portion 32 equivalent to one-half of the portion 22, and having a square cut end 32a'terminating in a diagonal edge 33 equivalent to diagonal edge 23. An edge 34, equivalent to edge 24, extends rearwardly to meet a cut 35 equivalent to cut 25.

The portion 29 comprises parts 42, 42a, 43, 44 and 45 equivalent respectively to parts 32, 32a, 33, 34 and 35 just described.

Edge portions 26 and 27 are disposed in parallel rela- I tion to the free edge of projecting portion 22. Edge portion 26 extends from a point medially of the length of edge 24 to a point medially of the length of edge 34. Similarly, edge portion 27 extends from a point medially of the length of edge 24a to a point medially of the length of edge 44. As will presently be made clear, edge portion 26, together with edges 24 and 34 and slits 25 and 35, constitute a female locking element. The same is true with edge portion 27 taken together with edges 24:: and 44 and slits 25a and 45.

Next, referring in detail to the male locking elements 19 and 20, these elements, as above stated, are identical with element 21. Element 19 has a forwardly projecting portion 52 equivalent to portion 22 of element 21; cut ends 52a, 52a equivalent to cut ends 22a, 22a; diagonal edges 53, 53 equivalent to edges 23, 23; rearwardly extending edges 54, 54a, equivalent to the rearwardly extending edges 24, 24a; and edges 55, 55a formed by slits and equivalent to the slit-formed edges 25, 25a.

Male locking element 20 has a forwardly projecting portion 62, cut ends 62a, 62a, diagonal edges 63, 63, rearwardly extending edges 64, 64a and edges 65, 65a equivalent to the respective parts 22, 22a, 22a, 23, 23, 24, 24a, 25 and 25a of locking element 21.

is formed 7 with two male looking elements 19 and 20, and closure An edge portion 66, equivalent to edge portions 26 and 27, extends between rearwardly extending edges 54 and 64, and edge portions 67 and 68 extend outwardly from points medially of the lengths of edges 54a and 64a. These edge portions 67 and 68 are approximately one-half the length of edge portions 26, 27 and 66, being severed from edge portions of an adjoining, nested blank which are equivalent to edge portions 32 and 42.

A female locking element is thus provided by the laterally projecting edge 66, rearwardly extending edges 54 and 64, and slit edges 55 and 65, this being identical to the female locking elements described above, disposed on each side of the male locking element 21 on flap 10.

In the process of closing an end of the carton and securing the flaps, the edge wall flaps 13 and 14 are first infolded, after which the flap is preferably folded down and flap 11 is folded flat against 'flap 10. Inward pressure is then applied to flap 11 and particularly upon the outer edges of the malelocking elements 19 and 20. This pressure is continued until the outer edges of the forwardly projecting portions 52 and 62 on elements 19 and 20 have moved far enough along the surface of the flap 10 to cause such outer edges to snap beneath the respective edge portions 27 and 26. As soon as this point is reached, pressure upon the elements 19 and 20 is released so that the natural resiliency of the paperboard will cause flaps 10 and 11 to move outwardly to their normal closing position, such as shown in FIG- URES l and2. This causes the diagonal lateral edge portions of the male locking elements to slip along each other with the result that these elements will come to rest in interlocked positions, as shown in FIGURE 2- The outer end portions of locking elements 19 and 20 will lie beneath flap 10, and the outer end portions of locking element 21 and the half-sections 28 and 29 will lie beneath flap 11.

The edges 25 and 25a of locking element 21, which are formed by slits, will be engaged'with edges parallel thereto on elements 19 and 20. That is, edge 25a will engage against edge 55 of element 19, and the edge 25 will engage against edge 65 of element 20. The opposite lateral portion of locking element 19 will be similarly engaged with parts on half-section 29. Specifically, edge 55a on element 19 will be engaged with edge 45 on section 29. It is to be noted that the engagement between the various edges referred to tends to prevent the locking elements from being pulled outwardly away from each other as would be the case when bulging pressure is applied from within a closed carton; or, similarly, when the carton is to be opened byapplying outward pulling force upon one or more of the exposed edges 66, 67 and 68, or edges 26 and 27, as shown in FIGURES 1 and 2.

Thus, under ordinary circumstances, when a carton is opened to remove its contents, the engagement between the locking parts is sutficiently strong to cause the lateral projections on the locking elements to become torn and frayed so that relocking of parts, once the carton is opened, cannot be accomplished effectively. This is due, not only to the tearing or fraying of the structure of the locking elements, but it also due to the fact that they will have become extensively bent or creased, thus reducing the natural resiliency of the parts in their uncreased condition. The carton may effectively be closed by moving it along fixed plow elements which engage the locking portions 19, 20, 21, 28 and 29 along their respective edges 52, 62, 22, 32 and 42 in such manner as to bend slightly or bow inwardly these male locking portions into positions in which they will slip beneath companion female locking portions, indicated at 27 for the portion 19, at 26 for the portion20, at 66 for the portion 21, at 68 for the portion 28, and at 67 for the portion 29. As soon as these male locking portions have slipped beneath the female locking portions and reached a condition 4 parallel with each other, they become securely locked and interlaced and such locked parts cannot readily be detached without creasing, fraying or otherwise disrupting them as above stated. This construction of the locking parts is also advantageous in cases in which a socalled tamper-proof carton is desired, due to the fact that, once the carton is opened and then reclosed, it will, in the usual case, be quite apparent that the carton has been opened.

As above indicated, the shape of the locking elements and half-sections 28 and 29 is such that identically shaped parts may be formed on an adjoining blank. The blanks may thus merely be separated from each other and are ready for use, there being no waste parts on either adjoining blank that requires stripping away and discarding.

It is further to be noted, as will be apparent from an inspection of FIGURE 1, that the portions of the flaps immediately inward of the edges 26, 27, 66, 67 and 68 form rigid extensions beyond the interlock line of the locking elements. These extended portions bear upon the surfaces of the opposed flaps and, due to their rigidity, they assist in keeping the composite closure flat and tend to resist inward deforming pressure upon the interlocked flaps.

p In the modified form of the carton, shown in FIG- URES 6, 7 and 8, the principles of construction and operation are the same as in the first described form. The difference of the modified form from the form first described is that the narrow projecting portions, such as that indicated at 22 on locking element 21, are eliminated and the diagonal edges, such as edges 23, 23, extend from the outer extremity of the locking element to meet the ends of the edges of the female locking element, such as edge 26 of the first form. As this modified form has more simplified contours, the dies for cutting the blanks are more economical and easier to prepare.

While the present description sets forth preferred forms of the invention, various changes may be made in the constructions disclosed without departing from the spirit of the invention, and it is therefore desired that the present disclosure be considered in all respects as illustrative and not restrictive, reference being bad to the appended claims rather than to the foregoing description to indicate the scope of the invention.

We claim:

1. A carton of resilient paperboard comprising:

(a) side walls and edge walls,

(b) opposed, infolding closure flaps hinged on the side walls,

(0) said flaps having rigid, outwardly projecting locking elements,

(d) two of the locking elements on one flap being symmetrically spaced with respect to a single locking element on the other flap so that such single locking element may be interfitted between said first two spaced locking elements,

(e) said locking elements being symmetrically and identically forme'd,

(f) each locking element having an elongated outer edge portion projecting parallel to the flap hinge line,

(g) each locking element having diagonal edges projecting outwardly and rearwardly toward the flap hinge line from such outer edge portion,

(h) rearwardly projecting edges extending from the ends of the diagonal edges and disposed at right angles to the outer edge portion,

(i) inwardly projecting edges extending from the ends of the rearwardly projecting edges, such inwardly projecting edges being parallel to the elongated outer edge portion of the locking element and terminating approximately in line with the respective outer ends of the elongated outer edge portion of the locking element,

(i) the inwardly projecting edges of the opposite coin locked position between said two. spaced locking operating locking elements being engageable with elements.

each other along an interlockline located medially References Cited by the Examiner between the carton side walls. h h UNITED STATES PATENTS 2. A carton as defined in claim 1, in w ie a rigid 5 projecting edge portion is provided on the closure flap 525;: having the .two spaced locking elements, said edge por 5/61 'ggg; tion being disposed between said spaced locking elements 3O37681 6/62 Kuchenbecker 229 39 and overlying the locking element on the opposite closure flap when suchvlocking element has been engaged FRANKLIN T. GARRETT, Primary Examiner. 

1. A CARTON OF RESILIENT PAPERBOARD COMPRISING: (A) SIDE WALLS AND EDGE WALLS, (B) OPPOSED, INFOLDING CLOSURE FLAPS HINGED ON THE SIDE WALLS, (C) SAID FLAPS HAVING RIGID, OUTWARDLY PROJECTING LOCKING ELEMENTS, (D) TWO OF THE LOCKING ELEMENTS ON ONE FLAP BEING SYMMETRICALLY SPACED WITH RESPECT TO A SINGLE LOCKING ELEMENT ON THE OTHER FLAP SO THAT SUCH SINGLE LOCKING ELEMENT MAY BE INTERFITTED BETWEEN SAID FIRST TWO SPACED LOCKING ELEMENTS, (E) SAID LOCKING ELEMENTS BEING SYMMETRICALLY AND IDENTICALLY FORMED, (F) EACH LOCKING ELEMENT HAVING AN ELONGATED OUTER EDGE PORTION PROJECTING PARALLEL TO THE FLAP HINGE LINE, (G) EACH LOCKING ELEMENT HAVING DIAGONAL EDGES PROJECTING OUTWARDLY AND REARWARDLY TOWARD THE FLAP HINGE LINE FROM SUCH OUTER EDGE PORTION, (H) REARWARDLY PROJECTING EDGES EXTENDING FROM THE ENDS OF THE DIAGONAL EDGES AND DISPOSED AT RIGHT ANGLES TO THE OUTER EDGE PORTION, (I) INWARDLY PROJECTING EDGES EXTENDING FROM THE ENDS OF THE REARWARDLY PROJECTING EDGES, SUCH INWARDLY PROJECTING EDGES BEING PARALLEL TO THE ELONGATED OUTER EDGE PORTION OF THE LOCKING ELEMENT AND TERMINATING APPROXIMATELY IN LINE WITH THE RESPECTIVE OUTER ENDS OF THE ELONGATED OUTER END PORTION OF THE LOCKING ELEMENT, (J) THE INWARDLY PROJECTING EDGES OF THE OPPOSITE COOPERATING LOCKING ELEMENTS BEING ENGAGEABLE WITH EACH OTHER ALONG AN INTERLOCK LINE LOCATED MEDIALLY BETWEEN THE CARTON SIDE WALLS. 